1. Field of the Invention
The present invention relates to electric energy generation in an electric power transmission system.
2. Description of the Related Art
Electric energy generation in an electric power transmission system can be useful for supplying ancillary electric devices.
For example, ancillary electric devices can be part of a monitoring system for surveying parameters of the electric power transmission system, which typically comprises electric conductors, junctions and terminations.
For example, WO 99/58992 discloses a power cable monitoring system comprising one or more transducers distributed along a sea cable. Power for the transducers and the transducer signal converters is supplied through electric conductors positioned in the data cable or through batteries.
The applicant observes that the use of batteries for feeding a monitoring system is expensive and may need maintenance. Indeed, batteries may need to be substituted, for example because exhausted, and this entails additional cost. In some instance, for example when the cable and the associated monitoring system is positioned in a remote or environmentally challenging location, the maintenance operation implies expensive means (e.g. for submarine cables) and/or the interruption of the power transmission (e.g. for high voltage cables).
At http://www.saprem.com/08—3—2_luminosaconductor.pdf, the company SAPREM S.A. de Preformados Metálicos discloses a warning light beacon for signalling the presence of cables suspended in high and medium tension overhead lines, which uses the field created by the conductor as a power supply. The warning light beacon has a transformer divided in two parts to make easier the installation on the conductor.